The present invention relates to the field of container closures, and more particularly, to a closure for a liquids container which provides for selective release of the contents of such container.
It is well-known to provide closures for liquids containers, such as beverage cups, which provide for selective release of their contents.
One class of closure comprises a one piece construction, with a main cover member that can be secured to the outer periphery of a beverage cup in a conventional manner, and which has a cut-away flap portion that can be selectively displaced between a closed position, whereat the flap is positioned substantially in line with the main cover member, and an open position, whereat the flap projects away from the main cover member, thereby to provide an opening for flow of the liquid contents of the beverage cup. U.S. Pat. No. 4,741,450 (Braude), issued May 3, 1988 and U.S. Pat. No. 5,799,814 (Schaefer et al.), issued Sep. 1, 1998 are both exemplary of this class, which is known to be capable of manufacture at relatively low cost, but can provide an unreliable liquid seal.
Another class of closure comprises two sections joined at their center. The outer section can be secured to the outer periphery of a beverage cup in a conventional manner, and forms an annular well which has a plurality of openings therein. The inner section is stressed such that it normally bears against the openings, thereby to provide a liquid seal between said openings and any contents of the container. When the center of the outer section is depressed, the inner section separates from the openings, thereby to permit fluid contents of the container to flow through the openings.
U.S. Pat. No. 3,797,696 (Debrell), issued Mar. 19, 1974; U.S. Pat. No. 3,727,808 (Fitzergerald), issued Apr. 17, 1973; and U.S. Pat. No. 3,730,399 (Dibrell et al.), issued May 1, 1973, are all exemplary of this latter class, which is known to be capable of providing a relatively liquid-tight seal, but suffers from the need for users to maintain pressure on the centre portion to permit fluid flow, which can be inconvenient.